1. Field of the Invention
The present invention relates to systems and methods for initiating flow of bulk materials in containment vessels, including transport vessels like trucks and hopper railcars.
2. Background
Bulk materials, like distillers grains for example, often are transported in containment vessels like trucks and hopper railcars. Distillers grains are a useful, fine-grain material byproduct of using corn, wheat, barley, and other grains in fermentation processes, like breweries and ethanol plants. Distillers grains can be “wet” or “dry.” Because of their high moisture content (up to 70% moisture) and the microbial growth such environments encourage, wet distillers grains have a relatively short shelf-life. Dry distillers grains (“DDGs”), on the other hand, have low moisture content (about 10-12% moisture) and can be stored for much longer periods without significant contamination. Although, DDGs are a byproduct, DDGs are readily marketable nonetheless as animal feed and, therefore, are frequently transported long distances in trucks and railcars.
3. Description of the Prior Art
A typical DDG transport vehicle is a covered “hopper” railcar. A hopper car is a type of railroad freight car used to transport loose bulk commodities such as coal, ore, grain, track ballast, and the like. This type of railcar is distinguished from a gondola car in that it has gravity discharge gates on the underside (belly-dump) or on the sides to discharge its cargo. Covered hopper cars are used for bulk cargo that must be protected from the elements, such as grain, sugar, and fertilizer. Hopper railcars typically have three, divided compartments, each compartment having its own belly-dump aperture or gate.
In such railcar systems, transported DDGs tend to settle and cake during transport as a result of horizontal and vertical compression, and heat and humidity, which prevents the material from being easily unloaded through the gravity discharge gates. Consequently, bulk materials that have become settled and caked during transport no longer flow freely through the gravity discharge gates and it takes significant time to unload such materials.
In order to loosen settled, caked, or hung-up material to initiate flow through the discharge gates, mechanical techniques are often employed and have proven to be either very time and labor intensive or damaging to the hopper car itself. These methods include shakers, vibrators, air lances, air cannons and mechanical probes or scrapers. Often a combination of methods is employed such as vibrating the car and striking the sides of the railcar with sledgehammers to try to dislodge the settled or hung-up material. The prior art also includes backhoe-style arm systems that attempt to scrape product out of the railcar with brute force, often resulting in damage to the railcar itself. Air cannon systems have also been used to try to loosen bulk materials but with limited results due to limitations of placement and actuation. Under these circumstances, it may take days to unload a single railcar using the approaches of the prior art.
Thus, there is a need for a system that can significantly reduce the time to unload bulk materials from containment vessels and transport vehicles like railcars and trucks. The disclosure herein accomplishes that objective by allowing an operator of the system to quickly and accurately position a blast of compressed air at points throughout the containment vessel to efficiently dislodge and initiate the flow of bulk particulate material from the vessel.